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PAPERS: Elly A Stolk, Jan J V Busschbach, Max Caffa, Eric J H Meuleman, and Frans F H Rutten Cost utility analysis of sildenafil compared with papaverine-phentolamine injections BMJ 2000; 320: 1165 [Abstract] [Full text]

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Scrupulous & Impartial ?

David Carvel   (2 May 2000)

45 000 phone calls?

Elly Stolk, Jan Busschbach   (12 May 2000)

Sticks and stones..

David Carvel   (13 May 2000)

Scrupulous & Impartial ? 2 May 2000
David Carvel, GP Glasgow G41 3EH Send response to journal: Re: Scrupulous & Impartial ?	Stolk et al ambitiously, and perhaps commendably, attempt to evaluate the cost effectiveness of sildenafil against papaverine-phentolamine in the treatment of erectile dysfunction. I have two misgivings about the paper however. Firstly the recruitment of subjects was dubious. Stolk et al randomly selected 45000 people from the Rotterdam telephone directory of whom 354 (0.79%) responded. I question how representative this sample is of the population as I personally would put the phone down on double-glazing salesmen never mind those asking about my uro-genital (dys)function. Rather than ask the partners of men with erectile dysfunction thay state "women were asked to imagine being a man with erectile dysfunction". In my opinion this hypothetical question is no more meaningful than a man being asked about the morbidity from menorrhagia or dysmenorrhea. It is silly and inconceivable. Over half of the recruited subjects failed to attend for interview because of inclement weather on that one day. There was no attempt to follow these self-selected subjects up. I have read of more rigorous data collecion. Secondly, the paper was sponsored with an "unrestricted grant" from Pfizer the sole manufacturer of sildenafil which has also sponsored all five authors previously. How impartial can the authors be I wonder when they for instance work on the assumption that PP injection is only accepted by 10% of men with ED but this figure is merely a personal communication from Pfizer's own market research. Unsurprisingly the conclusion is that sildenafil is cost effective. If, as Freemantle in his editorial says "QALY estimates are based on strong assumptions"*, how reliable are conclusions from drug-industry sponsored publications such as this? David Carvel MRCGP DRCOG *Freemantle N "Valuing the effects of sildenafil in erectile dysfunction" BMJ 2000;320:1156-1157
45 000 phone calls? 12 May 2000
Elly Stolk, institute for Medical technology Assessment, Erasmus University Rotterdam, Jan Busschbach Send response to journal: Re: 45 000 phone calls?	The reaction of David Carvel on our article about the cost- effectiveness of sildenafil shows signs of ignorance and foolishness. Of course we did not made 45 000 telephone calls as suggested by Carvel, but we continued recruiting until our sample of respondents was representative in terms of the distribution of sex, age and education. It is also unlikely that an university institute like iMTA would be interested in being just a continuation of a pharmaceutical firm. Independent research is the raison d'être of our institute. And of course, it is also very unlikely that we did not realise that women do not present erections. We performed this analysis from the societal perspective, the preferred perspective in health economics. As far as we see it, women are a part of that society which pays the insurance premium. An elaborate justification for these basic methodological issues can be found for free in the large study report at www.imta.nl. This report also describes an analysis based on patient values. This analysis from the patient's perspective gives similar results to the analysis from the societal perspective. For these apparent reasons, comments such as those of Carvel can never be a falsification of the finding that sildenafil has been shown to be a very cost-effectiveness medication. The real challenge is of course the general discussion about a decision making framework for new medications that prove to have an obviously better cost-effectiveness than medications already reimbursed. Elly Stolk Jan Busschbach
Sticks and stones.. 13 May 2000
David Carvel, GP Glasgow Send response to journal: Re: Sticks and stones..	Stolk's intemperate response and description of me as showing "signs of ignorance and foolishness" is not worthy of further debate. May its readers see this paper for what it is worth.